Dobby mechanisms for looms



Oct. 13, 1964 J. L. BULLEY ETAL mossy MECHANISMS FOR LOOMS Filed Dec.20, 1962 R b V.- mwuwm mm m mBm T QWMM Mnu i am LR 3m u United StatesPatent ice 3,152,619 DOBBY MECHANISMS FOR LOOMS John L. Bulley andFrederick W. Hole, Tiverton, Devon,

England, assignors to John D. Riordan, Hopkinton,

and Gertrude C. Libby, Stoughton, Mass.

Filed Dec. 20, 1962, Ser. No. 246,209 Claims priority, application GreatBritain, Jan. 3, 1962, 285/62 4 Claims. (Cl. 139-58) This inventionrelates to dobby mechanisms for looms.

It is well known that in the weaving of fabrics the warp threads arepassed through healds of a loom which are periodically raised andlowered horizontally to divide or shed the warp threads, so that theshuttle can carry the weft threads between the warp threads.

Dobby mechanisms are used in looms intended to weave relativelycomplicated patterns to control the shedding of the warp threads in asequence determined by a desired pattern of weaving.

It is an object of the invention to provide an improved dobby mechanismwhich is capable of operating at much higher speeds than knownmechanisms and which will positively control the motion of heald framescontaining the healds of the loom.

According to the present invention, there is provided a dobby mechanismcomprising a plurality of frame shafts arranged in a row, each frameshaft being pivotally connected to a heald frame and being verticallymovable to raise and lower the frame; a pair of pivotally mountedshedding arms arranged one on each side of the row of frame shafts andcapable of independently swinging up and down about their pivots toraise and lower the frame shafts; control means operable to swing theframe shafts about their pivotal connections with the heald frames froma neutral position into engagement with either one of the shedding armsin a sequence determined by a desired weaving pattern; and stop meansfor retaining the frame shafts, when they are disengaged from theshedding arms, in either the fully raised or the fully lowered positionunder the control of the control means.

The control means can be an arrangement of cams or chains or it can beelectric or electronic device capable of swinging the drive members in adetermined sequence.

The invention is particularly advantageous in its application to loomsfor weaving narrow fabrics, but is also applicable to looms for widefabrics.

A preferred embodiment of the invention is illustrated in theaccompanying drawing which is a perspective view of a dobby mechanismfor a narrow fabric loom.

The mechanism illustrated is arranged in a housing 1 and comprises aplurality of vertically disposed frame shafts 2 only one of which isshown in the drawing for reasons of clarity. These frame shafts 2 areconveniently metal strips arranged in a row with their faces presentedto one another. A heald frame 3 is connected at a pivot 4 to the top ofeach frame shaft 2, preferably in a way which permits the frame 3 to bedetached if desired.

A pair of horizontal drive levers or shedding arms 5 is arranged withone arm on each side of the row of frame shafts 2. These arms 5 aremounted on pivots 6, or on a common pivot, at one end so that the armscan be swung up and down independently of one another. The end portionsof the arms 5 remote from the pivots 6 are movable in shedding armguides 7 secured to one wall of the housing 1. Two eccentrics 8 aremounted on a horizontal drive shaft 9, are each connected by aconnecting rod 10 with one of the shedding arms 5 and are rotatable toraise and lower the arms 5 about their pivots 6 and consequently toraise and lower the heald frame 3. If desired, the connecting rods lit)and the eccentrics 8 can 3,152,619 Patented Oct. 13, 1964 be madeadjustable to allow the permitted vertical movement of the shedding arms5, and therefore heald frames 3, to be adjusted.

Each of the frame shafts 2 has a constricted waist portion 11intermediate its ends to provide recesses at opposite edges of theshafts 2. Each of these recesses can engage the adjacent shedding arm 5to enable its frame shaft to be raised or lowered. The frame shafts 2normally occupy a neutral position in which their recesses aredisengaged from both shedding arms 5, but they can be engaged with, ordisengaged from, either of the levers 5 in sequence by a control meansnow to be described.

This control means includes a plurality of control rods 12 each of whichis associated with one of the frame shafts 2, only one control rod beingillustrated in the drawing. Each control rod 12 has a pin-and-slotconnection 13 with its associated frame shaft 2 below the constrictedwaist portion 11. Each control is connected to, and is movable with, oneend of a slide or push-rod 14 having a cam follower roller 15 at theother end, the roller 15 being in engagement with the edge of a cam disc16; alternatively the disc 16 can be replaced by other cam means such asa chain. Each push-rod 14 is loaded by a spring 17 for movement in onedirection and is pushed in the opposite direction by the cam 16. Thus,the frame shafts 2 can be engaged with either one of the shedding arms 5or can be made to occupy the neutral position when it is disengaged fromboth arms 5, the sequence of movement being determined by the cams whichare selected in accordance with a desired weaving pattern. The cams 16are arranged as a unit on a cam shaft 18 mounted on a support bracket 19of the housing 1 and can be replaced by another unit when it is desiredtoweave another pattern. The cam shaft 18 is rotated by the drive shaft9 through a worm 20 and worm wheel 21.

It will be appreciated that the movements of the control rods could bedetermined by electric or electronic means if desired.

It is necessary for the frame shafts 2 to be retained periodically ineither the fully raised or fully lowered positions. For this purpose thelower end of each shaft 2 is vertically movable in a vertical slot 22 ina stop gate 23. Horizontal slots 24, 25 lead out of this vertical slot22 in positions respectively corresponding to the upper, lower limits ofmovement of shaft 2 and its heald frame 3 and form abutments in which aprojection 26 on the shaft 2 can engage when it is at the top and bottomof its stroke. The shaft 2 will then dwell at the top or bottom of itsstroke until urged by the control means into engagement with one of theshedding arms 5.

We claim:

1. A dobby mechanism comprising a plurality of frame shafts and healdframes arranged in a row, each frame shaft being pivotally connected toa heald frame and being vertically movable to raise and lower the frame;a pair of pivotally mounted shedding arms arranged one on each side ofthe row of frame shafts and capable of independently swinging up anddown about their pivots to raise and lower the frame shafts; controlmeans operable to swing the frame shafts about their pivotal connectionswith the heald frames from a neutral position in which they aredisengaged from both shedding arms into engagement with either one ofthe shedding arms in a sequence determined by a desired weaving pattern;and stop means for retaining the frame shafts, when they are disengagedfrom the shedding arms, in either the fully raised or the fully loweredposition under the control of the control means.

2. A mechanism as claimed in claim 1 wherein the control means comprisesa plurality of control rods each of which is connected with one of theframe shafts, springloaded push rods connected through said control rodswith the frame shafts and provided with cam follower rollers, arotatable cam shaft mounted adjacent to said rollers, and cams mountedon said cam shaft and rotatable therewith to displace the control rodsthereby to engage the frame shafts with, or disengage them from, eitherone of the shedding arms.

3. A mechanism as described in claim 1 including driving means for saidshedding arms comprising a rotatable shaft, eccentrics mounted on saidshaft, and adjustable connecting rods operatively connecting eachshedding arm to a respective eccentric.

4. A mechanism as described in claim 1, said stop means comprising afixed stop gate having a vertical slot therein for each frame shaft andtwo horizontal slots leading from each said vertical slot, and aprojection on each frame shaft arranged to enter one or the other ofsaid horizontal slots when the frame shaft is moved to its neutralposition at the top or bottom of its stroke.

References Cited by the Examiner UNITED STATES PATENTS 2,552,418 5/51Firing et a1. 139-58 2,811,986 11/57 Jacob et a1. 13955X 2,907,352 10/59Kronoff 13958 FOREIGN PATENTS 925,279 3/55 Germany.

16,973 1886 Great Britain.

21,747 1909 Great Britain.

9,116 8/94 Switzerland.

DONALD W. PARKER, Primary Examiner. RUSSELL C. MADER, Examiner.

1. A DOBBY MECHANISM COMPRISING A PLURALITY OF FRAME SHAFTS AND HEALDFRAMES ARRANGED IN A ROW, EACH FRAME SHAFT BEING PIVOTALLY CONNECTED TOA HEALD FRAME AND BEING VERTICALLY MOVABLE TO RAISE AND LOWER THE FRAME;A PAIR OF PIVOTALLY MOUNTED SHEDDING ARMS ARRANGED ONE ON EACH SIDE OFTHE ROW OF FRAME SHAFTS AND CAPABLE OF INDEPENDENTLY SWINGING UP ANDDOWN ABOUT THEIR PIVOTS TO RAISE AND LOWER THE FRAME SHAFTS; CONTROLMEANS OPERABLE TO SWING THE FRAME SHAFTS ABOUT THEIR PIVOTAL CONNECTIONSWITH THE HEALD FRAMES FROM A NEUTRAL POSITION IN WHICH THEY AREDISENGAGED FROM BOTH SHEDDING ARMS INTO ENGAGEMENT WITH EITHER ONE OFTHE SHEDDING ARMS IN A SEQUENCE DETERMINED BY A DESIRED WEAVING PATTERN;AND STOP MEANS FOR RETAINING THE FRAME SHAFTS, WHEN THEY ARE DISENGAGEDFROM THE SHEDDING ARMS, IN EITHER THE FULLY RAISED OR THE FULLY LOWEREDPOSITION UNDER THE CONTROL OF THE CONTROL MEANS.